The LIES based analysis technology is a technology for determining material composition of the sample by analyzing the plasma spectra generated by laser bombardment of the sample. The laser-induced breakdown spectroscopy has a series of advantages such as fast analyzing speed, simple experimental conditions, remote and on-line analysis, and thus, is presenting a booming trend in many fields such as steel and special alloy detection, coal quality detection and environmental monitoring. Owing to the small size, wide spectral range, high resolution and other characteristics, the echelle spectrometer is widely used in this field. As a key component in the whole instrument, the reliability of the calibration method of the echelle spectrometer has a crucial influence on the sensitivity and precision of the LIBS detection technology.
In the existing calibration methods of the echelle spectrometer, calibration is performed before measurement with a standard calibration light source (e.g., a mercury lamp), and data obtained thereafter are all measured based on this calibration. However, due to the characteristic of the spatiotemporal instability of the laser-induced plasma, spectral drift often occurs during measurement, which then affects the spectral intensity and wavelength precision and ultimately affects the sensitivity and precision of the material composition analysis.
Due to the above defects, there is an urgent need to solve this problem, i.e., to design a calibration method for echelle spectrometer in LIBS so as to overcome the shortcoming, i.e., the existing echelle spectrometer is only calibrated before measurement without solving the spectral line drift during use.